#include<stdio.h>
#include<math.h>
int main()
{
    double x, sum = 0, item = 0, fm = 1, sign = 1;
    scanf("%lf", &x);
    double fz = x;//没有输入x 的时候，不可以把x赋值给fz
    for(int i = 1; i <= 10; i ++)
    {
        item = sign * fz / fm * 1.0;
        sum += item;
        fz = fz * x * x;
        fm = fm *(2 * i) * (2 * i + 1);
        sign = - sign;
    }
    printf("%.3f", sum);
    return 0;
}